如何有条件地调用 ActiveRecord 的 where 中的属性？

Question

我有一段看起来像这样的代码：

foreign_object = (some_test) ? nil : <some foreign_object>

Document.where(foreign_id: foreign_object, status: "Working", ... )

如果foreign_object 为nil，它只会找到foreign_id = NULL 的文档。有没有办法有条件地把foreign_id放进去？我基本上想写：

Document.where(foreign_id: foreign_object if foreign_object, status: "Working", ...)

Answer 1

在这种情况下我会这样做：

 documents = Document.where(status: 'working')
 documents = documents.where(foreign_id: foreign_object) if foreign_object